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Date: Wed, 24 Oct 2012 14:53:11 -0500
From: Jacob Shin <jacob.shin@....com>
To: "H. Peter Anvin" <hpa@...or.com>
CC: Yinghai Lu <yinghai@...nel.org>,
"H. Peter Anvin" <hpa@...ux.intel.com>, Tom Rini <trini@...com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: BUG: 1bbbbe7 (x86: Exclude E820_RESERVED regions...) PANIC on
boot
On Wed, Oct 24, 2012 at 11:53:16AM -0700, H. Peter Anvin wrote:
> On 10/24/2012 09:48 AM, Jacob Shin wrote:
> >
> > hpa, we need this patch: https://lkml.org/lkml/2012/8/24/469 and the above
> > 2 from Yinghai to handle corner case E820 layouts.
> >
>
> I can apply Yinghai's patches, but the above patch no longer applies.
> Could you refresh it on top of tip:x86/u, please?
Sorry about that, it applied to Linus's 3.7-rc2 so I just assumed .. :-(
>From 7d2a67f6b435ede202bdf5d1982f9b5af90cce34 Mon Sep 17 00:00:00 2001
From: Jacob Shin <jacob.shin@....com>
Date: Wed, 24 Oct 2012 14:24:44 -0500
Subject: [PATCH] x86/mm: find_early_table_space based on ranges that are
actually being mapped
Current logic finds enough space for direct mapping page tables from 0
to end. Instead, we only need to find enough space to cover mr[0].start
to mr[nr_range].end -- the range that is actually being mapped by
init_memory_mapping()
This is needed after 1bbbbe779aabe1f0768c2bf8f8c0a5583679b54a, to address
the panic reported here:
https://lkml.org/lkml/2012/10/20/160
https://lkml.org/lkml/2012/10/21/157
Signed-off-by: Jacob Shin <jacob.shin@....com>
Tested-by: Tom Rini <trini@...com>
---
arch/x86/mm/init.c | 70 ++++++++++++++++++++++++++++++----------------------
1 file changed, 41 insertions(+), 29 deletions(-)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 8653b3a..bc287d6 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -29,36 +29,54 @@ int direct_gbpages
#endif
;
-static void __init find_early_table_space(unsigned long end, int use_pse,
- int use_gbpages)
+struct map_range {
+ unsigned long start;
+ unsigned long end;
+ unsigned page_size_mask;
+};
+
+/*
+ * First calculate space needed for kernel direct mapping page tables to cover
+ * mr[0].start to mr[nr_range - 1].end, while accounting for possible 2M and 1GB
+ * pages. Then find enough contiguous space for those page tables.
+ */
+static void __init find_early_table_space(struct map_range *mr, int nr_range)
{
- unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
+ int i;
+ unsigned long puds = 0, pmds = 0, ptes = 0, tables;
+ unsigned long start = 0, good_end;
phys_addr_t base;
- puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
- tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
+ for (i = 0; i < nr_range; i++) {
+ unsigned long range, extra;
- if (use_gbpages) {
- unsigned long extra;
+ range = mr[i].end - mr[i].start;
+ puds += (range + PUD_SIZE - 1) >> PUD_SHIFT;
- extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
- pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
- } else
- pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
-
- tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
+ if (mr[i].page_size_mask & (1 << PG_LEVEL_1G)) {
+ extra = range - ((range >> PUD_SHIFT) << PUD_SHIFT);
+ pmds += (extra + PMD_SIZE - 1) >> PMD_SHIFT;
+ } else {
+ pmds += (range + PMD_SIZE - 1) >> PMD_SHIFT;
+ }
- if (use_pse) {
- unsigned long extra;
-
- extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
+ if (mr[i].page_size_mask & (1 << PG_LEVEL_2M)) {
+ extra = range - ((range >> PMD_SHIFT) << PMD_SHIFT);
#ifdef CONFIG_X86_32
- extra += PMD_SIZE;
+ extra += PMD_SIZE;
#endif
- ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
- } else
- ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ /* The first 2/4M doesn't use large pages. */
+ if (mr[i].start < PMD_SIZE)
+ extra += range;
+
+ ptes += (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ } else {
+ ptes += (range + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ }
+ }
+ tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
+ tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
#ifdef CONFIG_X86_32
@@ -76,7 +94,7 @@ static void __init find_early_table_space(unsigned long end, int use_pse,
pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
printk(KERN_DEBUG "kernel direct mapping tables up to %#lx @ [mem %#010lx-%#010lx]\n",
- end - 1, pgt_buf_start << PAGE_SHIFT,
+ mr[nr_range - 1].end - 1, pgt_buf_start << PAGE_SHIFT,
(pgt_buf_top << PAGE_SHIFT) - 1);
}
@@ -85,12 +103,6 @@ void __init native_pagetable_reserve(u64 start, u64 end)
memblock_reserve(start, end - start);
}
-struct map_range {
- unsigned long start;
- unsigned long end;
- unsigned page_size_mask;
-};
-
#ifdef CONFIG_X86_32
#define NR_RANGE_MR 3
#else /* CONFIG_X86_64 */
@@ -263,7 +275,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
* nodes are discovered.
*/
if (!after_bootmem)
- find_early_table_space(end, use_pse, use_gbpages);
+ find_early_table_space(mr, nr_range);
for (i = 0; i < nr_range; i++)
ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
--
1.7.9.5
--
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